It is well known to employ concrete inserts to connect items to concrete structures after the concrete has been poured and hardened. Typically, an insert is embedded in a concrete ceiling so that pipe hangers or other objects may be connected to the ceiling by the insert after the concrete hardens.
A variety of metal concrete inserts are utilized in the prior art. Some inserts employ generally U-shaped sheet metal pieces to support rods which extend down through the ceiling. Such an arrangement is shown for example in my U.S. Pat. No. 5,205,690, issued Apr. 27, 1993. An insert employing a U-shaped plate also is illustrated as Item No. 276 on page 89 of the 1986 catalog published by Kin-Line, Inc., of Oakland, Calif. In the latter, an insert includes a U-shaped sheet metal piece which incorporates legs terminating in flanges that lie in a common plane and a bridge between the legs having a hole through which a threaded fastener is inserted. An internally threaded coupling is positioned between the legs of the U-shaped piece to butt against the bridge and a threaded fastener is screwed into the internal threaded cavity of the coupling and locked into place with a nut that abuts the bridge. The insert is constructed so that the threaded coupling is the same length as the legs of the U-shaped piece whereby the opening to the threaded coupling is in the plane of the concrete ceiling and the open end of the coupling is exposed at the bottom of a ceiling so that a threaded rod may be placed therein to support a pipe hanger or other object. U.S. Pat. No. 4,445,303, issued May 1, 1984, also discloses a concrete insert with a U-shaped component.
Inserts employing U-shaped members have certain drawbacks. For example, since the insert coupler terminates at the bottom of the concrete structure, adjustment and alignment are difficult during installation. And, of course, since the lower-most connector is embedded in the concrete, it cannot be removed or adjusted after the concrete hardens. Furthermore, U-shaped insert components can interfere with the flow of concrete and create voids in the vicinity of the insert which can adversely affect strength and performance. Also, the use of a U-shaped element dictates a minimum concrete depth. That is, the depth of the poured concrete structure must exceed the height of the insert, creating a situation which is not always desirable.
It is also known to employ deck inserts which employ a flat plate threadedly engaged with a rod which extends completely through the plate and through a hole in the metal decking or other support for the concrete. Such an arrangement, for example, is Item No. 293 on page 89 of the 1986 catalog published by Kin-Line, Inc. of Oakland, Calif. Such an approach has limited applicability and some inherent limitations. For example, when the anchor or upper end of the rod attached to the plate is moved up or down the lower end of the rod, by necessity, also moves up and down. This greatly limits the applicability of the device and necessitates the use of different rod lengths for different applications. For example, it may be desirable to have the bent upper end or anchor end of the rod project well up into the concrete and this may very well shorten the lower effective length of the rod to an undesirable degree.
Applicant is also aware of the following patent documents which are of record in applicant's U.S. Pat. No. 5,205,690: U.S. Pat. No. 1,088,290, issued Feb. 24, 1914, U.S. Pat. No. 3,405,497, issued Oct. 15, 1968, U.S. Pat. No. 4,325,178, issued Apr. 20, 1982, U.S. Pat. No. 4,854,086, issued Aug. 8, 1989, and French Patent No. 1132793 having an effective date of Nov. 5, 1956.
Also representative of the prior art are the inserts shown on page 155 of the B-Line System Inc. catalog made available by B-Line Systems Inc. of Highland, Ill. Applicant is also aware of the Ramset/Red Head steel deck insert made available by ITW of Wood Dale, Ill. and shown on page A42 of a 1992 publication designated Anchor Systems by that company.